But people who stuck with their exercise programs got the most benefits in terms of pain relief and mobility, regardless of the activity they chose.

Researcher Tatyana A. Shamliyan, MD, of the University of Minnesota School of Public Health, says many people with arthritis-related knee pain don’t exercise because it hurts, or they start an exercise program but quickly give it up.

“For people with osteoarthritis, exercise can increase knee pain, at least short-term, and that can be a big deterrent,” she says. “That is why it is so important to start under the supervision of a physical therapist.”

Knee Arthritis: Common Cause of Disability

Kneeosteoarthritis is a top cause of disability in the United States, affecting mostly older people.

According to the CDC, half of adults who reach the age of 85 will develop osteoarthritis-related knee pain. Two-thirds of obese adults will do the same in their lifetimes.

In the new review, published in the Nov. 6 issue of the Annals of Internal Medicine, Shamliyan and colleagues looked at 193 studies conducted between 1970 and 2012 that examined nonsurgical and non-drug treatments for osteoarthritis-related knee pain.

The studies measured the impact of the treatments on pain, disability, and quality of life.

While the studies showed a benefit for some activities, including low-impact aerobic exercise, water aerobics, and strength training, they were unable to show a benefit for others.

This does not mean that these therapies have no value in the treatment of arthritis-related knee pain, the authors conclude.

A major limitation of the study was that the researchers were only able to assess the impact of individual treatments, says University of Delaware assistant professor of physical therapy Joseph Zeni Jr., PhD.

He points out that physical therapy programs typically include a variety of different therapies, and the impact of any one on specific result such as pain, range of movement, and overall ability is difficult to determine.

Knee Pain Patients Aren’t All Alike

Snyder-Mackler is a colleague of Zeni’s at the University of Delaware.

“These studies looked at a single intervention because this is an easy thing to study, but it doesn’t tell us much about what is really happening in the real world,” she says.

She adds that individual patients need different approaches to physical therapy that take into account such things as their level of pain and disability, muscle strength, and range of motion.

“A good physical therapist will measure these things before coming up with a therapeutic strategy,” she says.

Zeni says an exercise program can make a huge difference in a patient’s quality of life, even when the patient is planning to have knee surgery.

“Many people think they don’t have to bother with exercise because they are going to have their knees replaced anyway,” he says. “But one of the biggest predictors of postoperative success is preoperative status. People who increase their strength and range of motion with exercise before surgery have the best outcomes.”

Weight Loss Helps Hurting Knees

According to one study, older adults with knee osteoarthritis who exercise at least three times a week can reduce their risk for arthritis-related disability by almost half.